The SOC of the entire pack is equal to the lowest SOC of any individual battery.

When You discharge a couple of batteries more than the others, You create a charging imbalance.

Since the charging system charges a single 48v pack (not individual batteries), the batteries that had a higher SOC will literally boil while the batteries with a lower SOC might not reach their full charge.

You need to discontinue using those 2 batteries for accessories and get a 48v->12v reducer.

You can also try to do a few dV/dT charging cycles by forcing an OBC reset.

All You have to do is disconnect the pack negative for more than 10 minutes.

The next time You charge the batteries, the OBC will run another "baseline" analysis which uses a different algorithm.

Let that charging cycle finish and check the voltages on the batteries again, if they are still far apart, disconnect the pack negative for more than 10 minutes and repeat the process.

The SOC of the entire pack is equal to the lowest SOC of any individual battery.

When You discharge a couple of batteries more than the others, You create a charging imbalance.

Since the charging system charges a single 48v pack (not individual batteries), the batteries that had a higher SOC will literally boil while the batteries with a lower SOC might not reach their full charge.

You need to discontinue using those 2 batteries for accessories and get a 48v->12v reducer.

You can also try to do a few dV/dT charging cycles by forcing an OBC reset.

All You have to do is disconnect the pack negative for more than 10 minutes.

The next time You charge the batteries, the OBC will run another "baseline" analysis which uses a different algorithm.

Let that charging cycle finish and check the voltages on the batteries again, if they are still far apart, disconnect the pack negative for more than 10 minutes and repeat the process.